Bulg. J. Phys. vol.27 no.1 (2000), pp. 084-088

Temperature Dependence of Magnetic Properties of LaSrMnO3 and (La0.67Ca0.33)MnO3 Systems By Ferromagnetic Resonance (FMR) Technique

S. Budak1, B. Aktaş2
1Fatih University, Faculty of Art and Science, Physics Department, 34900 Büyükçekmece, Istanbul, Turkey
2Institute of Technology, Physics Department, Gebze, Kocaeli, Turkey
Abstract. The magnetic properties of LaSrMnO3 and (La0.67Ca0.33)MnO3 systems were studied as a function of temperature by FMR technique. A quite strong FMR signal at low field (even zero) region appeared in addition to the main ferromagnetic resonance (FMR) peak of LaSrMnO3 at room temperatures. From the analysis of the FMR spectra of (La0.67Ca0.33)MnO3 it was found that a significant exchange anisotropy is induced at low temperatures. This anisotropy energy cants the local spin's direction and result in a colossal magneto-resistivity. The thin films of La-Ca-Mn-O system have also been studied after temperature annealing under different physical conditions (different temperature and oxygen treatment). The temperature annealing was observed to have significant effects on the magnetic properties of the system. The paramagnetic-ferromagnetic (perhaps spin glass) phase transition temperature drastically shifted to lower temperature for thin films case.

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